diff --git a/flows/src/main/java/com/softwaremill/jox/flows/Flow.java b/flows/src/main/java/com/softwaremill/jox/flows/Flow.java
index da1b9e2..6e45946 100644
--- a/flows/src/main/java/com/softwaremill/jox/flows/Flow.java
+++ b/flows/src/main/java/com/softwaremill/jox/flows/Flow.java
@@ -15,6 +15,7 @@
 import java.util.concurrent.atomic.AtomicLong;
 import java.util.concurrent.atomic.AtomicReference;
 import java.util.function.BiFunction;
+import java.util.function.BinaryOperator;
 import java.util.function.Consumer;
 import java.util.function.Function;
 import java.util.function.Predicate;
@@ -178,13 +179,12 @@ public T runLast() throws Exception {
      * @throws NoSuchElementException
      *   When this flow is empty.
      */
-    public <U extends T> U runReduce(BiFunction<U, U, U> f) throws Exception {
-        AtomicReference<Optional<U>> current = new AtomicReference<>(Optional.empty());
+    public T runReduce(BinaryOperator<T> f) throws Exception {
+        AtomicReference<Optional<T>> current = new AtomicReference<>(Optional.empty());
         last.run(t -> {
-            // noinspection unchecked
             current.updateAndGet(currentValue -> currentValue
-                    .map(u -> f.apply(u, (U) t))
-                    .or(() -> Optional.of((U) t)));
+                    .map(u -> f.apply(u, t))
+                    .or(() -> Optional.of(t)));
         });
 
         return current.get().orElseThrow(() -> new NoSuchElementException("cannot reduce an empty flow"));
diff --git a/flows/src/test/java/com/softwaremill/jox/flows/FlowRunOperationsTest.java b/flows/src/test/java/com/softwaremill/jox/flows/FlowRunOperationsTest.java
index cbf5fc0..ac3bd8d 100644
--- a/flows/src/test/java/com/softwaremill/jox/flows/FlowRunOperationsTest.java
+++ b/flows/src/test/java/com/softwaremill/jox/flows/FlowRunOperationsTest.java
@@ -230,7 +230,7 @@ void runTakeLast_shouldReturnLastNElementsFromSource() throws Exception {
     @Test
     void runReduce_shouldThrowNoSuchElementExceptionForReduceOverEmptySource() {
         // given
-        Flow<Object> flow = Flows.empty();
+        Flow<Integer> flow = Flows.empty();
 
         // when & then
         NoSuchElementException exception = assertThrows(NoSuchElementException.class, () -> flow.runReduce(Integer::sum));